🌐 Mailman 3 June 2022 - Tutor - python.org

Re: [Tutor] problem solving with lists: final (amateur) solution
by marcus.luetolf＠bluewin.ch July 18, 2022

July 18, 2022

Hello Experts, hello dn, it's a while since I - in terms of Mark Lawrence - bothered you with my problem. Thanks to your comments, especially to dn's structured guidance I've come up with the code below, based on repeatability. I am shure there is room for improvement concerning pythonish style but for the moment the code serves my purposes. A commented version can be found on https://github.com/luemar/player_startlist. def startlist(all_players, num_in_flight): c_all_players = all_players[:] history = {'a':[], 'b':[],'c':[],'d':[],'e':[],'f':[],'g':[],'h':[],\ 'i':[],'j':[],'k':[],'l':[],'m':[],'n':[],'o':[],'p':[]} print('...............day_1................') def day_1_flights(): key_hist = list(history.keys()) c_key_hist = key_hist[:] for dummy_i in c_key_hist: print('flights_day_1: ', c_key_hist[:num_in_flight]) for key in c_key_hist[:num_in_flight]: [history[key].append(player)for player in c_all_players[0:num_in_flight]] del c_key_hist[:num_in_flight] del c_all_players[0:num_in_flight] day_1_flights() def day_2_to_5_flights(): flights = {} for i in range(2,6): print('...............day_' + str(i)+'................') flights['a_flight_day_'+str(i)]= [] flights['b_flight_day_'+str(i)]= [] flights['c_flight_day_'+str(i)]= [] flights['d_flight_day_'+str(i)]= [] lead = list('abcd') flight_list = [flights['a_flight_day_'+str(i)], flights['b_flight_day_'+str(i)],\ flights['c_flight_day_'+str(i)], flights['d_flight_day_'+str(i)]] for j in range(len(flight_list)): def flight(cond, day): for player in all_players: if player not in cond: day.extend(player) cond.extend(history[player]) history[lead[j]].extend(player) day.extend(lead[j]) day.sort() [history[pl].extend(day) for pl in day[1:]] return lead[j]+'_flight_day_'+str(i)+ ': ' + str(flight_list[j]) conditions = [history[lead[j]], history[lead[j]] + flights['a_flight_day_'+str(i)],\ history[lead[j]] + flights['a_flight_day_'+str(i)] + \ flights['b_flight_day_'+str(i)], \ history[lead[j]] + flights['a_flight_day_'+str(i)] + \ flights['b_flight_day_'+str(i)]+ flights['c_flight_day_'+str(i)]] print(flight(list(set(conditions[j])), flight_list[j])) day_2_to_5_flights() startlist(list('abcdefghijklmnop'), 4) Many thanks, Marcus. -----Ursprüngliche Nachricht----- Von: Tutor <tutor-bounces+marcus.luetolf=bluewin.ch(a)python.org> Im Auftrag von dn Gesendet: Mittwoch, 25. Mai 2022 22:02 An: tutor(a)python.org Betreff: Re: [Tutor] problem solving with lists: preliminary solution Hi Marcus, This is a bit of 'blast from the past' - and I haven't gone 'back' to look at our previous correspondence/this message hasn't "threaded". May I offer a few criticisms and suggestions:- On 26/05/2022 05.19, marcus.luetolf(a)bluewin.ch wrote: > ....sorry, forgott correct e_mail address..... > > Hello Experts, hello dn, and not forgetting @wlfraed who mentioned university research papers dealing with the intricacies (and insolubles) of the "SGP". Did you try following-up on any of those? > In resuming my task to write code for a special constellation of the > "SocialGolferProblem" (SGP) : > number_of_days (number_of_weeks) = 5 > number_of_flights (number_of_groupings) = 4 seize of flight > (players_per_grouping) = 4 Criticism: although each of these terms is perfectly understandable, and easily converted into a 'readable' pythonic identifier, later the code uses "n" (for example) - which of the two values commencing "*n*umber_" is it? > and given the solution below (draws for week 1 through 5) I've come up > with a code of which I only post part of it (for it gets to big): > for day 1( hardcoded) and for day 2 (as a function to be used through > day 5). The word "hardcoded" immediately stopped me in my tracks! The whole point of using the computer is to find 'repetition' and have the machine/software save us from such boredom (or nit-picking detail in which we might make an error/become bored). That said, may I suggest that you grab a whiteboard/blackboard, or a convenient wall and a bunch of Post-It notes, and try to solve the problem manually - first for week-one (which is largely trivial), but then recording the 'history' and moving-on to the extra decision-layer for week-two. If your brain doesn't go 'click'*, go on to deal with week-three and see how the algorithm develops... * keeping my 'pocket handkerchief' lawn tidy doesn't require 'heavy machinery', but after many years of service my little electric mower 'died'. I bought a new Bosch model which needed to be partly assembled from the box. The accompanying manual featured explanations in dozens of languages. However, the (single/all-language) diagram showing where the back-wheels were to be joined to the axles featured (only) the English explanation: "Click". Perhaps other languages do use the word (?spelling), but the term "going click in your mind" has long been used for the idea explained in today's idiom as an "ahah! moment". > The crucial part of my functions for day 2 to 5 are the conditional > statements. These conditional statements do not follow a consistent pattern. > This inconsistency casts some doubt on the effectiveness of my code > below and I'd appreciate critical comments. > ... > a_flight_day_1 = [] > b_flight_day_1 = [] > c_flight_day_1 = [] ... > history = {'a':[], > 'b':[],'c':[],'d':[],'e':[],'f':[],'g':[],'h':[],'i':[],'j':[],'k':[],'l':[] ,'m':[],'n':[],'o':[],'p':[]} ... Following-on from talking about looping (repetition), yes we need to use multiple conditional expressions to ensure that history is taken into account (consistently). The other 'side' of both of these code-constructs is the data-construct. Code-loops require data-collections! The hard-coded "a" and "day_1" made me shudder. (not a pretty sight - the code, nor me shuddering!) Would you benefit from spending a little time, putting aside the SGP for a moment, and looking at a tutorial on "nesting" lists (and dictionaries) in Python? Again, the above-mentioned 'whiteboard' exercise may help 'reveal' the patterns in the data, as well as identifying an algorithm. Sadly, the 'hard-coded' parts may 'help' sort-out week-one, but (IMHO) have made things impossibly-difficult to proceed into week-two (etc). (and I'm back to mentioning that I haven't searched for our previous discussions - specifically whether we talked-about a data-construct for 'history', and also to referring-back to the 'whiteboard' suggestion) We were warned! The SGP can be made to work for this particular combination of weeks/flights/players. Which gives credence to the first-thought: "it looks so easy". However, the wider problem is more complex than one at-first imagines! This is the reason why 'combinatorial problems' are so interesting. Did I say "interesting"? Perhaps "frustrating" and/or "frustratingly difficult to solve" - or even: 'cannot (always) be solved'! This is no 'little kitten' or some old piece of rope, you have "a tiger by the tail"... -- Regards, =dn _______________________________________________ Tutor maillist - Tutor(a)python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor

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Feedback on coding style
by Leam Hall June 26, 2022

June 26, 2022

Hey all, I'm looking for general Python code critique, feel free to share snarky comments. :) The parameters are: 1. Code to Python 3.6 or so. 2. Use only the standard library or locally created modules. 3. Keep it clean and simple so new Pythonistas can understand and contribute. Let me know how to make this better. Leam -- Automation Engineer (reuel.net/resume) Scribe: The Domici War (domiciwar.net) General Ne'er-do-well (github.com/LeamHall) ### #!/usr/bin/env python3 # name: bp_tracker.py # version: 0.0.1 # date: 20220509 # author: Leam Hall # desc: Track and report on blood pressure numbers. # Notes: # Datafile expects three ints and one float, in order. # TODO # Add statistical analysis for standard deviation. # Report based on time of day (early, midmorning, afternoon, evening) # (?) Add current distance from goal? import argparse from datetime import datetime import os.path def array_from_file(report_file): data = [] with open(report_file, 'r') as file: for line in file: line.strip() datum = line.split() if len(datum) == 4: data.append(datum) else: continue return data def report(report_data): highest_systolic = 0 highest_diastolic = 0 highest_pulse = 0 latest = -1.0 for datum in report_data: systolic = int(datum[0]) diastolic = int(datum[1]) pulse = int(datum[2]) date = float(datum[3]) if systolic > highest_systolic: highest_systolic = systolic highest_systolic_event = datum if diastolic > highest_diastolic: highest_diastolic = diastolic highest_diastolic_event = datum if pulse > highest_pulse: highest_pulse = pulse highest_pulse_event = datum if date > latest: latest_record = datum print("Highest Systolic: {}/{} {} {}".format(*highest_systolic_event)) print("Highest Diastolic: {}/{} {} {}".format(*highest_diastolic_event)) print("Highest Pulse: {}/{} {} {}".format(*highest_pulse_event)) print("Latest Record: {}/{} {} {}".format(*latest_record)) def result_string(report_list): return "{} {} {} {}".format(*report_list) report_file = "bp_numbers.txt" parser = argparse.ArgumentParser() parser.add_argument("-a", "--add", nargs=3, help = "Add in the order of systolic, diastolic, pulse") parser.add_argument("-f", "--file", help = "Report file") args = parser.parse_args() if args.file: report_file = args.file if args.add: # This format allows sequencing now and parsing later. timestamp = datetime.now().strftime("%Y%m%d.%H%M") this_report = args.add this_report.append(timestamp) with open(report_file, 'a') as file: file.write(result_string(this_report) + "\n") else: # Default behavior is to report. if os.path.exists(report_file): try: report_data = array_from_file(report_file) report(report_data) except: print("Error processing report data") else: print("Cannot find ", report_file) ###

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Event loop logic question
by Phil June 25, 2022

June 25, 2022

Thank you for reading this. What I'm trying to achieve here is have the word 'stop' printed once whenever no keys are pressed and 'forward' printed once even when the up arrow key is held down. I don't think this question needs any knowledge of Pygame Zero to solve and it's quite likely that I've misunderstood the logic required. The following code is my most recent version which seems to work the first time through the loop but fails after subsequent 'up' key presses. Debugging the event loop is difficult. Any hints or alternative methods will be, as always, greatly appreciated. By the way, this project sends commands to a controller which is easily overwhelmed if too many commands are received per second. import pgzrun WIDTH = 20 HEIGHT = 20 direction = 'stop' stop_flag = True forward_flag = True def on_key_down(key): global direction if key == keys.UP: print('up pressed') direction = 'forward' forward_flag = True print('forward_flag ', forward_flag) elif key == keys.SPACE: direction = 'quit' def on_key_up(key): global direction #print('stop') direction = 'stop' stop_flag = True def update(): global direction, stop_flag, forward_flag if direction == 'stop' and stop_flag: print('stop') stop_flag = False elif direction == 'forward' and forward_flag: print('forward') forward_flag = False stop_flag = True elif direction == 'quit': quit() pgzrun.go() -- Regards, Phil

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make a sqlite3 database from an ordinary text file
by Manprit Singh June 21, 2022

June 21, 2022

Dear Sir, I was trying to make a sqlite3 data base from an ordinary text file named abcd.txt on my computer. it has data as given below in the form of 2 columns Time Pieces 1 10 2 15 3 25 4 31 5 40 6 45 7 53 8 54 9 65 10 75 Below given is the code that makes sqlite3 database work.db, with a table named workdata, which will be having 2 columns Time & Pieces . The code lateron fetches all data from the table. import sqlite3 def data_generator(workfile): with open(workfile) as obj: obj.readline() for line in obj: yield tuple(line.split()) con = sqlite3.connect("work.db") cur = con.cursor() cur.execute("create table workdata(Time INT, Pieces INT)") cur.executemany("insert into workdata values (?, ?)", data_generator("abcd.txt")) con.commit() cur.execute("select Time, Pieces from workdata") print(cur.fetchall()) cur.close() con.close() In this example i am using generator function for iterator to be used in executemany(). I will not prefer a list comprehension in this case as a file may contain a large number of rows . Is there any better way to do this task ? Kindly suggest. Regards Manprit Singh

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Help with brute force approach to solving grid combinations
by tempest.amogh June 20, 2022

June 20, 2022

As a personal project, I was inspired by Erik Demaine. He has created a font based on tetris shapes [http://erikdemaine.org/fonts/], however I would like to emulate this but based on another reference. I want to write an algorithm that brute force solves all the positions for these pieces in the english alphabet. I am having trouble making a grid that can be solved with these pieces, despite a book saying so. I have attached the image that shows the shapes [http://erikdemaine.org/fonts/tetris/kadon_fonts.jpg]. My code: --- import numpy as np default_grid = np.array([[0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0] ]) a_grid = np.array([[0, 0, 0, 0, 0, 0], [0, 0, -1, -1, 0, 0], [0, 0, -1, -1, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, -1, -1, 0, 0], [0, 0, -1, -1, 0, 0] ]) # 1. SHAPES # 1.1 DOMINOES shape_straight2 = np.array([[7, 0, 0, 0, 0, 0], [7, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0] ]) shape_flat = np.array([[0, 0, 0, 0, 8, 8], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0] ]) # 1.2 TRIMINOES shape_corner = np.array([[6, 0], [6, 6] ]) shape_straight3 = np.array([[7], [7], [7] ]) # 1.3 TETRIMINOES shape_straight = np.array([[1, 1, 1, 1] ]) shape_straight1 = np.array([[1], [1], [1], [1] ]) shape_square = np.array([[2, 2], [2, 2] ]) shape_l = np.array([[3, 0], [3, 0], [3, 3] ]) shape_l2 = np.array([[0, 3], [0, 3], [3, 3] ]) shape_l3 = np.array([[3, 3, 3], [0, 0, 3] ]) shape_l4 = np.array([[3, 3, 3], [3, 0, 0] ]) shape_skew = np.array([[4, 4, 0], [0, 4, 4] ]) shape_skew2 = np.array([[4, 0], [4, 4], [0, 4] ]) shape_skew3 = np.array([[0, 4, 4], [4, 4, 0] ]) shape_skew4 = np.array([[0, 4], [4, 4], [4, 0] ]) shape_t = np.array([[5, 0], [5, 5], [5, 0] ]) shape_t2 = np.array([[5, 5, 5], [0, 5, 0] ]) shape_t3 = np.array([[0, 5], [5, 5], [0, 5] ]) shape_t4 = np.array([[0, 5, 0], [5, 5, 5] ]) new_shape = np.array(default_grid + shape_t4) --- I ran a test with just inserting one shape into a grid. But the following error messages comes up. In the final code, I want there to be a way to check the coordinates and insert the shapes there will many for loops and if elif statements. Error Message: 120, in <module> new_shape = np.array(default_grid + shape_t4) ValueError: operands could not be broadcast together with shapes (6,6) (2,3) — Regards, Amogh Atwe

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Help with brute force algorithm
by tempest.amogh June 19, 2022

June 19, 2022

As a personal project, I was inspired by Erik Demaine. He has created a font based on tetris shapes [http://erikdemaine.org/fonts/], however I would like to emulate this but based on another reference. I want to write an algorithm that brute force solves all the positions for these pieces in the english alphabet. I am having trouble making a grid that can be solved with these pieces, despite a book saying so. I have attached the book that shows the shapes, and some pseudocode. I would appreciate any possible guidance. Thank you very much :) — Regards, Amogh Atwe

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writing to an address in memory
by Nathan Smith June 14, 2022

June 14, 2022

Hi! I'm working with a library which written in C and has a callback function for listening for data, basically. Essentially any time it wants new data, it calls the callback with arguments: callback(handle, buffer, length) Where bufffer is a pointer to the buffer to write the data to. I know how to read the data (using ctypes.from_address) but I don't know how to write data to it? I've tried Googling, but I think my research is being hampered that I may not be using the correct termonology? The library I am working with is: http://www.un4seen.com/doc/#bass/STREAMPROC.html -- Best Wishes, Nathan Smith, BSC My Website: https://nathantech.net

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Issue with running iPython
by Anmol Sharma June 12, 2022

June 12, 2022

I just installed python on win 10 and installed Anaconda distribution. I get the following error while using ipython.Python error - self._poll(timeout) RuntimeError: <overlapped.Overlapped object at <0> still has pending operation at deallocation, process may crash This error is coming without any code also. SO, if i just load ipython and it taken me to ipython prompt, then If I just press "enter" multiple times, it gives this error. I also imported the necessary packages - import platform, asyncio if platform.system() == 'Windows': asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy()) And then I just load ipython and without even writing any line of code, I just press enter 2-3 times and I get this error - (base) C:\Users\03987N744\Training_notebook>ipython -i --no-banner enumerate_vs_range.py In [1]: In [1]: In [1]: Traceback (most recent call last): File "C:\Users\Anaconda3\lib\asyncio\windows_events.py", line 439, in select self._poll(timeout) RuntimeError: <_overlapped.Overlapped object at 0x0000022127E19DB0> still has pending operation at deallocation, the process may crash -- Also, this seems to be specific to *i*python and jupyter notebooks... It does not occur on python.... Regards Anmol Sharma

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Learning Object Oriented Programming
by Aliyan Navaid June 11, 2022

June 11, 2022

Hello, I aspire to learn AI with python and learned the basics of python such as datatypes, iteration, selection. However now I’m stuck as there is so much in the field of AI, what should my next move be? Learning OOP? Libraries such as SciPy? Tensor flow? Statistics? Thanks in advance.

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Gaussian to image
by Gaurav Shukla June 7, 2022

June 7, 2022

Hello, Is there a way to convert Gaussian curves to a greyscale image simulating a CCD image? So basically my Gauss has an x-value and y-value with multiple Gaussian's, which one generally get from a CCD/sCMOS experimentally. I have generated a Gaussian spectrum (with four peaks) based on atomic physics calculations, I would then try to read with another code that would read the image and give back the Gaussian spectrum. I am very new so any help would be highly appreciated. Thanks DG

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